Improving the predictive quality of time‐dependent density functional theory calculations of the X‐ray emission spectroscopy of organic molecules

Fouda, Adam A. E.; Besley, Nicholas A.

Abstract

The simulation of x-ray emission spectra of organic molecules using time-dependent density functional theory (TDDFT) is explored. TDDFT calculations using standard hybrid exchange-correlation functionals in conjunction with large basis sets can predict accurate X-ray emission spectra provided an energy shift is applied to align the spectra with experiment. The relaxation of the orbitals in the intermediate state is an important factor, and neglect of this relaxation leads to considerably poorer predicted spectra. A short-range corrected functional is found to give emission energies that required a relatively small energy shift to align with experiment. However, increasing the amount of Hartree-Fock exchange in this functional to remove the need for any energy shift led to a deterioration in the quality of the calculated spectral profile. To predict accurate spectra without reference to experimental measurements, we use the CAM-B3LYP functional with the energy scale determined with reference to a ∆self-consistent field (SCF) calculation for the highest energy emission transition.

Citation

Fouda, A. A. E., & Besley, N. A. (2020). Improving the predictive quality of time‐dependent density functional theory calculations of the X‐ray emission spectroscopy of organic molecules. Journal of Computational Chemistry, 41(11), 1081-1090. https://doi.org/10.1002/jcc.26153

• Journal Article Type: Article
• Acceptance Date: Jan 8, 2020
• Online Publication Date: Jan 22, 2020
• Publication Date: Apr 30, 2020
• Deposit Date: Jan 23, 2020
• Publicly Available Date: Jan 23, 2020
• Journal: Journal of Computational Chemistry
• Print ISSN: 0192-8651
• Electronic ISSN: 1096-987X
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Volume: 41
• Issue: 11
• Pages: 1081-1090
• DOI: https://doi.org/10.1002/jcc.26153
• Keywords: General Chemistry; Computational Mathematics
• Public URL: https://nottingham-repository.worktribe.com/output/3787403
• Publisher URL: https://onlinelibrary.wiley.com/doi/full/10.1002/jcc.26153
• Additional Information: Received: 2019-10-15; Accepted: 2020-01-08; Published: 2020-01-22